The present invention relates to a Dynamic Imaging Camera (DIC) or Scanning Camera (SCAN) having Cadmium-Telluride (Cd—Te, including Cd—Zn—Te) based radiation detectors for imaging X-ray signals. Cd—Te based detectors for imaging X-ray signals are known in the art, and are particularly useful for high energy radiation imaging. High energy radiation imaging include X-ray and gamma ray radiation in the 1.0 KeV and greater range. Typically, these detectors have a blocking contact on one face and pixel contacts on another face. In turn, the pixel contacts are bump-bonded to charge integrating application specific integrated circuits (ASICs). The blocking contact serves to reduce the dark or ambient current of the detector by a factor of 3 to 10. Lower dark currents mean higher sensitivity to incoming x-rays (signal).
However, a problem can exist in a Cd—Te detector having a blocking contact. Such contacts (e.g., Indium based blocking contacts) can polarize after a few seconds of operation, i.e., one to several hundreds of seconds. Polarization means that the detector starts to loose signal and the image loses definition or acuity and gets more blurry. Polarization happens due to gradual electric charge trapping inside the material bulk of the Cd—Te detector. Previously, one could not use a Cd—Te detector material in this X-ray imaging mode for more than a few seconds, due to the polarization effect.
Therefore, it would be useful in the field to have a means for preventing or overcoming the effect of electric charge trapping in high energy X-ray imaging systems utilizing Cd—Te based radiation detectors.